feat(feeds): add generic RSS support (#410)

* feat(feeds): add generic rss support

* feat(feeds/web): add generic rss support

* implement rss downloading

* gosum + mod

* re-add size from Custom field.

* implement uploader + category

* sync

* remove double assignment (+torznab)

* didn't save the rss file >.>

* cleanup

* fixfeeds): create rss indexer

* fix(feeds): stop feed

* feat(feeds): support nexusphp rss enclosure link

* feat(feeds): check size for custom size

* fix(feeds): race condition and only stop enabled feeds

* fix(feeds): unify indexer implementation badge

Co-authored-by: Kyle Sanderson <kyle.leet@gmail.com>

internal/indexer/definitions/rss_generic.yaml

@@ -0,0 +1,22 @@
+---
+#id: rss
+name: Generic RSS
+identifier: rss
+description: Generic RSS
+language: en-us
+urls:
+  - https://domain.com
+privacy: private
+protocol: torrent
+implementation: rss
+supports:
+  - rss
+source: rss
+
+rss:
+  minInterval: 15
+  settings:
+    - name: url
+      type: text
+      required: true
+      label: RSS URL